dlib C++ Library - ffmpeg_file_to_speaker_ex.cpp

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
/*
 This is an example illustrating the use of the ffmpeg wrappers.
 It attempts to read audio from a microphone if available, and saves the audio to wav.
*/
#include <iostream>
#include <chrono>
#include <dlib/media.h>
#include <dlib/cmd_line_parser.h>
using namespace std;
using namespace std::chrono;
using namespace std::chrono_literals;
using namespace dlib;
using namespace dlib::ffmpeg;
int main(const int argc, const char** argv)
try
{
 command_line_parser parser;
 parser.add_option("i", "input audio file", 1);
 parser.add_option("o", "output audio device (speaker). E.g. hw:0,0", 1);
 parser.add_option("codec", "audio codec. E.g. pcm_s16le", 1);
 parser.set_group_name("Help Options");
 parser.add_option("h", "alias of --help");
 parser.add_option("help", "display this message and exit");
 parser.parse(argc, argv);
 const char* one_time_opts[] = {"i", "o", "codec"};
 parser.check_one_time_options(one_time_opts);
 if (parser.option("h") || parser.option("help"))
 {
 parser.print_options();
 return 0;
 }
 
 const std::string filename = get_option(parser, "i", "");
 const std::string device = get_option(parser, "o", "hw:0,0");
 const std::string codec = get_option(parser, "codec", "");
 if (device.empty())
 {
 cout << "Didn't find a speaker. Exiting.\n";
 return EXIT_FAILURE;
 }
 // Open file
 demuxer cap({filename, video_disabled, audio_enabled});
 if (!cap.is_open())
 {
 cout << "Failed to open " << device << endl;
 return EXIT_FAILURE;
 }
 // Create writer to speaker
 muxer writer([&] {
 muxer::args args;
 args.filepath = device;
 args.output_format = "alsa";
 args.enable_image = false;
 args.args_audio.codec_name = codec;
 args.args_audio.sample_rate = 44100;
 args.args_audio.channel_layout = AV_CH_LAYOUT_STEREO;
 args.args_audio.fmt = cap.sample_fmt();
 return args;
 }());
 if (!writer.is_open())
 {
 cout << "Failed to open wav file" << endl;
 return EXIT_FAILURE;
 }
 // Pull and push
 frame f;
 while (cap.read(f))
 writer.push(std::move(f));
 return EXIT_SUCCESS;
}
catch (const std::exception& e)
{
 printf("%s\n", e.what());
 return EXIT_FAILURE;
}